1. The high molecular weight RNA of Visna virus
- Author
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J Tamalet, P. Filippi, M. Brahic, and L. Delbecchi
- Subjects
Hot Temperature ,Virus Cultivation ,Visna-maedi virus ,Visna virus ,viruses ,Nucleic Acid Denaturation ,Tritium ,Biochemistry ,Melting curve analysis ,Virus ,chemistry.chemical_compound ,Centrifugation, Density Gradient ,Animals ,RNA Viruses ,Urea ,Dimethyl Sulfoxide ,Centrifugation ,Denaturation (biochemistry) ,Uridine ,Sheep ,biology ,RNA ,General Medicine ,biology.organism_classification ,Molecular biology ,Culture Media ,Molecular Weight ,Sedimentation coefficient ,chemistry ,Choroid Plexus ,Nucleic Acid Conformation ,RNA, Viral - Abstract
Summary Visna virus was grown on sheep choroid plexus cells in the presence of tritiated uridine. The culture medium was harvested every 2 h (« 2 h virus ), or every 24 h (« 24 h virus ). RNA was extracted from purified virus by treatment with 1 p. cent sodium dodecylsulfate followed by centrifugation through a linear sucrose gradient. The main component, which sedimented at 66S, was pooled and further characterized. This RNA was heterogeneous as shown by resedimenting various fractions from the 66S peak. Two hours virus gave more heterogeneous RNA than 24 h virus. Denaturation of the 66S RNA by heat, urea or dimethylsulfoxide resulted in a shift of the sedimentation coefficient. Denatured 66S RNA from 24 h virus sedimented as a very heterogeneous material between 4 and 20 S, whereas denatured 66S RNA from 2 h virus was essentially made of a 36S component. This difference resulted from an intraviral degradation of the RNA as demonstrated by incubating purified 2 h virus at 37°C and examining its denatured RNA at different times. After 24 h of incubation the 36S peak was changed into slowly sedimenting RNA. A large extent of secondary structure in the 66S RNA, capable of hiding this degradation, was demonstrated by its melting curve. 66S RNA from 24 h virus was less stable at elevated temperature than its counterpart from 2 h virus, as expected for a partially degraded molecule.
- Published
- 1973
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